1. Field of the Invention
The invention concerns parts made from thermoplastics which contain polyphenylene ether (PPE) and from rubber, as well as methods for their production.
2. Discussion of the Background
It is known from DE-OS No. 36 02 705 that parts which are supposed to demonstrate both high strength and rubber elasticity can be produced by covulcanization of thermoplastics which contain PPE and rubbers which contain double bonds. The method has the great advantage that a strong bond is created between the thermoplastic and the rubber within a very short period of time. In this regard, it represents a significant improvement as compared with previous methods, which either do not make a sufficiently strong bond possible or were significantly more complicated.
However, the use of this method is limited in view of the rubbers. While an SBR rubber, for example, can be covulcanized with the thermoplastic which contains PPE without restriction, there are problems with NR rubber, for example. According to the theory of DE-OS No. 36 02 705, a bond with an NR rubber can only be achieved if a mixture of NR rubber and at least 5% SBR rubber is used. This restriction is considered undesirable in practical situations. There is also an interest in achieving a bond between thermoplastics which contain PPE and pure NR rubber. But even if a mixture of 5% SBR rubber and 95% NR rubber is used, the bonding values are clearly lower than those of pure SBR rubber. Similar methods are carried out with other types of rubber. DE-OS No. 36 02 705 does not offer any indication of how one could achieve a strong bond in these problematical cases. In general, there is a need for an alternative method, in order to produce parts with a strong bond between a thermoplastic which contains PPE and any desired rubber.